HIGH-EXPANSION BONDING GLASS HAVING IMPROVED WATER RESISTANCE AND USES THEREOF

Abstract

The present disclosure relates to a bonding glass which has improved water resistance and has a coefficient of thermal expansion (25-300) of from 14.Math.10.sup.6K.sup.1 to 17.Math.10.sup.6K.sup.1, comprising, in mol % on an oxide basis, 5-7 of B.sub.2O.sub.3, 10-14 of Al.sub.2O.sub.3, 36-43 of P.sub.2O.sub.5, 15-22 of Na.sub.2O, 12.5-20 of K.sub.2O, 2-6 of Bi.sub.2O.sub.3 and >0-6 of R oxide, where R oxide is an oxide selected from the group consisting of MnO.sub.2 and SiO.sub.2 and SnO.sub.2 and Ta.sub.2O.sub.5 and Nb.sub.2O.sub.5 and Fe.sub.2O.sub.3 and GeO.sub.2 and CaO. The bonding glass is free of PbO except for, at most, impurities. The bonding glass may have a glass transition temperature Tg of from 390 C. to 430 C. The present disclosure also relates to uses of this bonding glass.

Claims

1. A bonding glass which has improved water resistance and has a coefficient of thermal expansion (25-300) of from 14.Math.10.sup.6K.sup.1 to 17.Math.10.sup.6K.sup.1, comprising a composition in mol % on an oxide basis of: TABLE-US-00005 B.sub.2O.sub.3 4-8; Al.sub.2O.sub.3 10-14; P.sub.2O.sub.5 36-43; Na.sub.2O 15-22; K.sub.2O 12.5-20; Bi.sub.2O.sub.3 2-6; and R oxide >0-6, wherein R oxide is an oxide selected from the group consisting of MnO.sub.2, SiO.sub.2, SnO.sub.2, Ta.sub.2O.sub.5, Nb.sub.2O.sub.5, Fe.sub.2O.sub.3, GeO.sub.2, CaO, or any combination thereof, the composition being free of PbO except for, at most, impurities.

2. The bonding glass according to claim 1, wherein the bonding glass has a glass transition temperature Tg of from 390 C. to 430 C.

3. The bonding glass according to claim 1, wherein R oxide comprises, in mol % on an oxide basis, 3.0-6.0 MnO.sub.2.

4. The bonding glass according to claim 3, wherein R oxide comprises, in mol % on an oxide basis, 3.2-4.9 MnO.sub.2.

5. The bonding glass according to claim 1, wherein R oxide comprises, in mol % on an oxide basis, at least one of: TABLE-US-00006 SiO.sub.2 0.01-1.8; GeO.sub.2 0.01-2.8; SnO.sub.2 0.01-2.4; Fe.sub.2O.sub.3 0.01-2.1; Ta.sub.2O.sub.5 0.01-2.2; Nb.sub.2O.sub.5 0.01-2.0; or CaO 0.01-0.4.

6. The bonding glass according to claim 1, wherein the composition comprises, in mol % on an oxide basis, at least one of: TABLE-US-00007 P.sub.2O.sub.5 36-<42; B.sub.2O.sub.3 5.5-6.8; Al.sub.2O.sub.3 11.4-12.8; Na.sub.2O 15.4-20.9; K.sub.2O 12.8-19.8; or Bi.sub.2O.sub.3 2.5-4.5.

7. The bonding glass according to claim 1, wherein the composition comprises at least one alkali metal oxide and a total content of alkali metal oxides in the composition is at most 36 mol %.

8. The bonding glass according to claim 7, wherein the at least one alkali metal oxide is selected from the group consisting of Li.sub.2O, Na.sub.2O K.sub.2O, Cs.sub.2O, or any combination thereof.

9. The bonding glass according to claim 1, wherein the bonding glass has crystalline regions which comprise phosphate-containing crystal phases.

10. The bonding glass according to claim 9, wherein the crystal phases comprise crystals from the group consisting of a Bi.sub.2O.sub.3P.sub.2O.sub.5 system, an R.sub.2OAl.sub.2O.sub.3P.sub.2O.sub.5 system, or any combination thereof.

11. The bonding glass according to claim 10, wherein the crystal phases comprise crystals from a K.sub.2OAl.sub.2O.sub.3P.sub.2O.sub.5 system.

12. The bonding glass according to claim 1, wherein the composition is in the form of a glass powder.

13. The bonding glass according to claim 1, further comprising a metal bonded to the bonding glass to form a glass-metal composite.

14. The glass-metal composite according to claim 13, wherein the metal is one of a lightweight metal and a lightweight metal alloy.

15. The glass-metal composite according to claim 13, wherein the metal is selected from the group consisting of aluminum, aluminum alloys, titanium, titanium alloys, magnesium, magnesium alloys, AlSiC, steel, stainless steel, copper, or copper alloys.

16. The glass-metal composite according to claim 13, wherein the bonding glass is covered, at least in sections, by a covering glass or a covering polymer.

17. The glass-metal composite according to claim 16, wherein the bonding glass is covered, at least in sections, by a covering glass having a higher water resistance than the bonding glass and comprising a titanate glass.

18. A device, comprising: a feedthrough, comprising: at least one main element composed of a metal and which has at least one opening formed therethrough; a functional element passed through the at least one opening and embedded in a bonding glass in the at least one opening, the bonding glass sealing the at least one opening, the bonding glass comprising a composition in mol % on an oxide basis of: TABLE-US-00008 B.sub.2O.sub.3 4-8; Al.sub.2O.sub.3 10-14; P.sub.2O.sub.5 36-43; Na.sub.2O 15-22; K.sub.2O 12.5-20; Bi.sub.2O.sub.3 2-6; and R oxide >0-6, wherein R oxide is an oxide selected from the group consisting of MnO.sub.2, SiO.sub.2, SnO.sub.2, Ta.sub.2O.sub.5, Nb.sub.2O.sub.5, Fe.sub.2O.sub.3, GeO.sub.2, CaO, or any combination thereof, the composition being free of PbO except for, at most, impurities.

19. The device according to claim 18, wherein the bonding glass hermetically seals the at least one opening.

20. The device according to claim 18, wherein the functional element is, at least in a region of the at least one opening, an essentially pin-shaped conductor.

21. The device according to claim 20, wherein the pin-shaped conductor comprises, at least in the region of the at least one opening, at least one of copper or aluminum.

22. The device according to claim 18, wherein the metal is at least one of a lightweight metal and a lightweight metal alloy.

23. The device according to claim 18, further comprising a housing holding the at least one feedthrough.

24. The device according to claim 23, wherein the housing comprises a metal bonded to the bonding glass to form a glass-metal composite.

25. The device according to claim 18, wherein the device is at least one of an electrical device, an electronic device, or an electrochemical device selected from the group consisting of batteries, rechargeable batteries, capacitors, supercapacitors, sensor housings, actuator housings, microcontroller housings, medical implants, articles configured to be installed on a human body or an animal body, diagnostic instruments, or therapeutic instruments.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0087] FIG. 1 is a cross-sectional view of an exemplary embodiment of a feedthrough formed according to the present disclosure; and

[0088] FIG. 2 is a cross-sectional view of an exemplary embodiment of a feedthrough formed according to the present disclosure with a covering material.

[0089] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0090] Table 1 shows working examples of compositions formed according to the present disclosure of the bonding glass in mol % on an oxide basis, with WE denoting a working example of a bonding glass formed according to the present disclosure.

[0091] In Table 2, bonding glasses which are not formed according to the present disclosure have been examined as comparative examples, with CE denoting a comparative example.

[0092] The water resistance of all working examples was determined as described previously. According to the test results, a classification of the water resistance as good, satisfactory and unsatisfactory was made. The evaluation of the resistance was effected visually by the 4-eye principle: [0093] Good: Specimen geometry and colour unchanged [0094] Satisfactory: Specimen of defined geometry, slight colour & transparency change [0095] Unsatisfactory: Sample geometry and colour changed

[0096] The resistance to LP 30 and the water-containing electrolyte described were likewise determined for most of the bonding glasses formed according to the present disclosure.

[0097] The glasses were examined in respect of electrolyte resistance using an 882 mm glass piece. The examination was carried out on the basis of the components leached from the test specimen, in particular alkali metals Li, Na, K and/or P and/or Bi after 10, 20, 30 and not more than 40 days.

[0098] The evaluation of the resistance was effected visually according to the 4-eye principle:

[0099] The bulk material was categorized as follows: [0100] Good: Specimen geometry and colour unchanged [0101] Satisfactory: Specimen of defined geometry, slight colour & transparency change [0102] Unsatisfactory: Specimen geometry and colour changed

[0103] The electrolyte solution was likewise categorized visually: [0104] Good: Electrolyte: NO colour change [0105] Satisfactory: Electrolyte: slight colour change [0106] Unsatisfactory: Electrolyte: dark coloration

TABLE-US-00003 TABLE 1 Working Examples WE1 WE2 WE3 WE4 WE5 WE 6 WE 7 WE8 WE 9 WE10 WE11 B.sub.2O.sub.3 6.2 6.2 6.1 5.85 6.1 6.5 5.9 6.15 6.15 6.25 6 Al.sub.2O.sub.3 12.15 12.25 11.85 12.2 12.35 12.5 11.2 12.1 12 12.05 12.1 P.sub.2O.sub.5 40.55 38 39.5 38.2 38.3 38.7 41.7 41.7 41.7 41.6 41.75 Bi.sub.2O.sub.3 3.45 3.75 2.85 3.7 3.8 3.8 3.4 4.4 4.4 4.5 4.4 Li.sub.2O Na.sub.2O 15.9 16.8 15.9 16.45 16 20.4 16.1 16.05 16.2 15.9 16.1 K.sub.2O 17.65 18.7 18.85 19 19 13.3 17.5 17.65 17.5 17.7 17.7 BaO CaO 0.1 0.15 0.15 0.3 0.15 0.1 MnO.sub.2 3.75 3.9 4.5 4 4.05 4.4 SiO.sub.2 0.25 0.25 0.3 0.3 0.25 0.3 4.2 0.05 0.05 0.15 0.15 GeO.sub.2 SnO.sub.2 2 Fe.sub.2O.sub.3 1.8 Ta.sub.2O.sub.5 1.9 Nb.sub.2O.sub.5 1.85 PbO Total 100 100 100 100 100 100 100 100 100 100 100 Total R oxide 4.1 4.3 4.95 4.6 4.45 4.8 4.2 1.95 2.05 2 1.95 Tg [ C.] 401 407 411 409 404 425 411 421 416 422 413 Sft [ C.] 567 CTE[25; 300] 16.2 16.23 15.48 16.22 16.16 15 16.4 15.5 16.1 16 15.8 CTE[25; Tg] 18.7 Water resistance good good good good good good good good good good good Water-containing good good good good good good satisfactory electrolyte LP 30 good good good good good good good WE12 WE13 WE14 WE15 WE16 WE17 WE18 WE19 WE20 WE21 WE22 B.sub.2O.sub.3 6.3 7 7 5.2 7 6.9 6.9 6.9 6.9 6.9 5.85 Al.sub.2O.sub.3 12.2 13 13 11.1 13 13 13 13 13 13 12.5 P.sub.2O.sub.5 41.4 36.1 39.3 42 39.3 39.3 39.3 39.3 39.5 39.5 38.75 Bi.sub.2O.sub.3 3.6 5.8 5.8 4.6 5.8 5.8 5.8 5.8 5.8 5.8 3.85 Li.sub.2O Na.sub.2O 15.9 20.4 20.4 21.3 20.4 20.4 20.4 20.4 20.4 20.4 17.25 K.sub.2O 18 14.38 14.38 12.5 14.38 14.4 14.3 14.3 14.3 14.3 16.3 BaO CaO 0.12 0.12 0.1 0.12 0.1 MnO.sub.2 3.2 3.2 4 SiO.sub.2 0.05 1.4 GeO.sub.2 2.55 0.2 SnO.sub.2 0.3 Fe.sub.2O.sub.3 0.3 Ta.sub.2O.sub.5 0.1 Nb.sub.2O.sub.5 0.1 PbO Total 100 100 100 100 100 100 100 100 100 100 100 Total R oxide 2.6 3.32 0.12 3.3 0.12 0.2 0.3 0.3 0.1 0.1 5.5 Tg [ C.] 420 Sft [ C.] CTE[25; 300] 16 16.6 16.6 15.8 16.3 16.3 16.2 16.2 16.2 16.2 15.7 CTE[25; Tg] Water resistance good good good good good good good good good good good Water-containing unsatisfactory electrolyte LP 30 good

[0107] In Table 2, G denotes good, S denotes satisfactory, and U denotes unsatisfactory.

TABLE-US-00004 TABLE 2 Comparative Examples CE1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 CE9 CE10 B.sub.2O.sub.3 6 5.8 7.6 5.4 5 3.6 6.9 4.8 7.6 4.7 Al.sub.2O.sub.3 12 12.3 4.2 2 9 10.75 13 8.6 4.2 8.7 P.sub.2O.sub.5 40 43.55 46.5 46.4 36.6 48.1 39.5 43.3 47.5 43.3 Bi.sub.2O.sub.3 0 4.4 1 1.4 2 3.9 5.8 0 0 0 Li.sub.2O 7.7 17.3 Na.sub.2O 15 15.8 28.3 28.4 15 16.1 20.4 17.3 28.3 K.sub.2O 18 18.05 12.4 16.3 19.5 17.5 14.4 17.3 12.4 17.3 BaO 8.7 8.7 CaO 0.05 SiO.sub.2 0.1 0.05 0.05 ZnO Cs.sub.2O PbO 9 5.2 Total 100 100 100 100 100 100 100 100 100 100 Total R oxide 0 0.1 0 0.1 0 0.05 0 0 0 0 Tg [ C.] 401 425 339 286 334 407 375 325 354 CTE[25; 300] 16.3 15.9 19.7 19.2 16.7 16.4 16.5 19 14.9 CTE[25; Tg] 23.8 Water resistance S S U U U U S U U U Water-containing U S U U S G electrolyte LP 30 electrolyte G U G G G G CE11 CE12 CE13 CE14 CE15 CE16 CE17 CE18 CE19 B.sub.2O.sub.3 4.8 4.8 5.2 1.8 4.7 8.9 9.4 13.6 8.7 Al.sub.2O.sub.3 2 2 12.7 9.4 9.5 6.6 6.35 5 6.4 P.sub.2O.sub.5 43.3 37.1 39.5 38.4 37.9 35.5 35.35 32.7 32.8 Bi.sub.2O.sub.3 2.9 2.3 2 3.9 4 3.3 Li.sub.2O 34.6 42.1 6.9 7.4 Na.sub.2O 16.5 19.8 16.4 23.1 32.3 26.2 17.9 K.sub.2O 19 17.9 19.1 17 11.2 18.5 23.5 BaO 15.3 14 CaO SiO.sub.2 0.1 0.1 1.5 ZnO 10.3 12.4 Cs.sub.2O 4.1 PbO Total 100 100 100 100 100 100 100 100 100 Total R oxide 0 0 0.1 10.4 12.4 0 1.5 0 0 Tg [ C.] 369 359 367 341 360 350 349 CTE[25; 300] 13.7 14.8 19.1 18.9 17.4 21 19.9 21.0 22.9 CTE[25; Tg] Water resistance U U U U U U U U U Water-containing S electrolyte LP 30 Electrolyte G G G U S

[0108] All working examples of the bonding glasses formed according to the present disclosure display good water resistance. This applies for all of the R oxides mentioned. It is noted that although good water resistances are achieved in the case of WE11 and WE12, the resistance to water-containing electrolytes is significantly poorer. This shows that attack of water-containing electrolytes on the bonding glass occurs not only via the water, but likewise via the electrolyte salts and also the other substances present in the electrolyte. However, the bonding glasses corresponding to WE11 and WE12 also have good resistance to the nonaqueous electrolyte LP30. However, CE5 and CE17 show that the resistance of bonding glasses to water-containing electrolytes can be much better than that to water.

[0109] Tables 1 and 2 likewise show the values for Tg. Tg is simple to determine and gives an indication of the fusion or processing temperature. Although Tg is significantly below these, the lower the Tg, the lower is the fusion or processing temperature, too. Since in all working examples Tg is far below the melting point of, in particular, lightweight metals, these are also suitable for producing joints to lightweight metals and/or metals having a similarly low melting point.

[0110] All bonding glasses formed according to the present disclosure in Table 1 display high expansion, i.e. they have a CTE which makes them suitable for producing joints to the metals mentioned, such as lightweight metals.

[0111] Furthermore, all bonding glasses formed according to the present disclosure in Table 1 bond to the metals mentioned, in particular lightweight metals, so well that a hermetic seal between bonding glass and metal is formed.

[0112] The bonding glasses formed according to the present disclosure thus simultaneously satisfy many requirements, such as good water resistance, a high CTE and a low processing temperature or Tg, which make it possible to produce joints with the metals mentioned, such as lightweight metals, and also good resistance to the nonaqueous electrolyte LP30 and, in some embodiments, good resistance to water-containing electrolytes.

[0113] Comparison of the working examples formed according to the present disclosure in Table 1 with the comparative examples in Table 2 shows that, despite similar base glass systems, the presence of the abovementioned R oxide leads to a very significant improvement in the water resistance. Interestingly, all comparative examples in Table 2 display satisfactory water resistances at best, some comparative examples display unsatisfactory water resistance. When, for example, WE2 is compared with CE2, it is found that the P.sub.2O.sub.5 content differs significantly: in the case of CE2, the P2O5 content is greater than that of glass formed according to the present disclosure and the glass has a significantly lower water resistance and an unsatisfactory resistance to LP30.

[0114] Table 2 shows the comparative examples CE1 to CE19, which represent bonding glasses which are not formed according to the present disclosure. The water resistance of the bonding glasses of all the comparative examples CE1 to CE19 are not more than satisfactory. Some are even unsatisfactory. In comparison, the bonding glasses formed according to the present disclosure comprising the R oxide as a constituent of the composition have an at least good water resistance, which is thus significantly improved compared to the prior art. CE18 and CE19 even devitrify during production of the joint and are therefore unusable for producing the latter.

[0115] On the other hand, if the proportion of P.sub.2O.sub.5 is reduced, an improved water resistance is expected, but the coefficient of thermal expansion is likewise reduced to such an extent that a bond to lightweight metals is no longer possible.

[0116] Most embodiments of the bonding glasses formed according to the present disclosure also have a good resistance to water-containing electrolytes. The same applies to the chemical resistance compared to the above-described nonaqueous electrolytes.

[0117] The composition of the bonding glass formed according to the present disclosure is accordingly balanced in such a way that a number of requirements are satisfied simultaneously. These are, in particular, the water resistance, the coefficient of thermal expansion and, in some embodiments, the chemical compatibility with lightweight metals, which is a prerequisite for producing a joint. In some applications, the bonding glass has to be able to wet the lightweight metal. There is an interaction between all the abovementioned components of a bonding glass formed according to the present disclosure, which leads to the abovementioned prerequisites being satisfied. The present disclosure provides, in some embodiments, a composition range for bonding glasses having improved water resistance and the coefficient of thermal expansion of which makes production of joints to lightweight metals possible.

[0118] Close examination of the working examples shows that a complex interaction of the components, such as P.sub.2O.sub.5 and the alkali metals, and also Bi.sub.2O.sub.3 and R oxide, has to be in the indicated composition ranges, which results in the improvement in the water resistance compared to the comparative examples and thus to the bonding glasses known from the prior art.

[0119] Owing to the complexity of this interaction, the result is surprising and was not foreseeable.

[0120] Referring now to FIG. 1, an exemplary embodiment of a feedthrough 1 formed according to the present disclosure is illustrated. The feedthrough 1 comprises as a conductor, which may be a pin-shaped conductor, a metal pin 3 which may consist of one material, for example aluminum or copper, and also, as main element 5, a metal part which, in some embodiments, consists of a low-melting metal, i.e. a lightweight metal, such as aluminum. The metal pin 3 is passed through an opening 7 which goes through the metal part 5. Although only a single metal pin going through the opening is shown, it is also possible for a plurality of metal pins to be passed through the opening.

[0121] The outer contour of the opening 7 can be round or oval. The opening 7 goes through the entire thickness D of the main element or metal part 5. The metal pin 3 is fused into a glass material 10 and is passed in the glass material 10 through the opening 7 through the main element 5. The glass material 10 is the bonding glass formed according to the present disclosure. The opening 7 is introduced into the main element 5 by, for example, a parting process, such as stamping. In order to provide a hermetic seal where the metal pin 3 is passed through the opening 7, the metal pin 3 is fused into a glass plug composed of the glass material 10 formed according to the present disclosure. This method of production avoids squeezing-out of the glass plug together with metal pin from the opening 7, even under increased loads on the glass plug, e.g. in the case of a compressive load. The fusion temperature of the glass material formed according to the present disclosure to the main element is from 20 K to 100 K below the melting temperature of the material of the main element 5 and/or of the pin-shaped conductor.

[0122] The feedthrough depicted in FIG. 2 corresponds to the feedthrough of FIG. 1, except that the covering material 11, which can, as described, be a covering polymer or a covering glass, has been applied to the glass material or glass plug 10. The covering material 11 is, in some embodiments, the previously described titanate glass.

[0123] The covering material 11 can be applied to the outside of the feedthrough. The outside is opposite the inside. The inside may be the inside of a housing. The glass material 10 may therefore be in contact with the electrolytes, which may be of a battery and/or a rechargeable battery and/or a capacitor and/or a supercapacitor. The glass material 10 of the glass plug consequently has to be resistant to this electrolyte. As stated above, the bonding glass formed according to the present disclosure is resistant to water and to the water-containing and/or nonaqueous electrolytes examined. The covering material 11 on the outside does not come into contact with the electrolytes, but instead with the environmental conditions. Accordingly, the covering material 11 can be optimized for different properties, e.g. for further-improved water resistance, for impact strength, for abrasion resistance, etc. The titanate glass described is, for example, not as resistant to water-containing and nonaqueous electrolytes as the bonding glass formed according to the present disclosure, but may be even more water-resistant.

[0124] The composition of the bonding glass formed according to the present disclosures as described herein provides very high coefficients of thermal expansion which are in the range from 14.Math.10.sup.6K.sup.1, such as in the range from 15.Math.10.sup.6K.sup.1, to 17.Math.10.sup.6K.sup.1 for temperatures in the range from 20 C. to 300 C. and thus in the region of the thermal expansion of lightweight metals such as aluminum, but also of similar metals for the essentially pin-shaped conductors 11 which are passed through the glass material, for example copper. Thus, aluminum has a thermal expansion =23.Math.10.sup.6K.sup.1, copper of 16.5.Math.10.sup.6K.sup.1, at room temperature. In order to prevent the lightweight metal of the main element, and possibly also of the metal pin, from melting or deforming during glazing-in, the melting temperature of the glass material is below the melting temperature of the material of the main element and/or conductor.

[0125] The fusion temperature of the glass composition to be used is then in the range from 250 C. to 650 C. The glazing-in of the essentially pin-shaped conductor 3 into the main element 5 before seating of the feedthrough in the opening 7 is achieved by the glass being heated together with the conductor, such as the pin-shaped conductor, to the fusion temperature of the glass, so that the glass material softens and encloses the conductor in the opening and lies against the main element 9. If, as indicated above, aluminum is, for example, employed as lightweight metal having a melting point T.sub.melting=660.32 C. for the main element 9, the fusion temperature of the glass material may be, as indicated above, in the range from 350 C. to 640 C.

[0126] The material of the pin-shaped conductor 3 may be identical to the material of the main element, or at least belongs to the same class of materials. The material of the conductor can be, particularly in electrochemical applications, selected according to the electrolytes used and the function in the cell. The pin-shaped conductor can comprise aluminum, an aluminum alloy, AlSiC, copper, a copper alloy, CuSiC alloys or NiFe alloys, a copper core material, e.g., an NiFe jacket having a copper interior, or CF25, i.e., a cobalt-iron alloy, silver, a silver alloy, gold or a gold alloy as material.

[0127] The feedthrough described herein is suitable for a pressed glazing-in. Here, the bonding glass is placed together with the at least one conductor in a housing part and/or main element and then heated so that all elements fuse together. During cooling, the bonding glass solidifies and the housing part and/or main element contracts more strongly than the glass. Owing to the different coefficients of thermal expansion of the materials used, the bonding glass is placed under compression in the opening of the feedthrough and forms a seal. The coefficient of thermal expansion of the joining partner, here generally the metal, in particular the lightweight metal, is greater than that of the bonding glass.

[0128] The glass embedding comprising the glass material indicated in Table 1 forms, as described above, a hermetic seal. This applies particularly to feedthroughs produced using the glass materials indicated. All glasses indicated were tested in feedthroughs with aluminum as material of the main element and were found to form a hermetic seal.

[0129] A lightweight metal such as aluminum (Al), AlSiC, an aluminum alloy, magnesium, a magnesium alloy, titanium and/or a titanium alloy may be employed as material for the main element. Alternative materials for the main element are metals such as steel, rust-free steel, stainless steel or tool steel.

[0130] The glass compositions formed according to the present disclosure provide bonding glasses, which may be used in joints to lightweight metals, having a low process temperature, a fusion temperature which is lower than the melting point of aluminum, a high coefficient of expansion a and an excellent resistance to battery electrolytes and significantly improved water resistance. Although the glass compositions have been described for use in feedthroughs, such as battery feedthroughs, they are not restricted thereto; other fields of application are, for example, the sealing of housings, of sensors and/or actuators or else capacitors and/or supercapacitors. In principle, the feedthroughs are suitable for all purposes in lightweight construction, in particular as feedthroughs in electric components which have to be light and heat-resistant. Such components occur, for example, in aircraft construction and in space flight. Use in medical technology, such as in diagnostic instruments and/or in implants, is likewise possible.

[0131] The high-expansion bonding glasses formed according to the present disclosure are much more resistant to water than known high-expansion bonding glasses. It is presumed that this is a result of the interplay between Bi.sub.2O.sub.3 and the R oxide described, which apparently stabilize, at least in regions, the network of the glass matrix so that the sensitive constituents thereof, such as phosphorus constituents thereof, are not leached out, or at least leached out less readily. At the same time, the bonding glasses formed according to the present disclosure can form a particularly hermetic seal with lightweight metals. This makes the bonding glasses formed according to the present disclosure useful in highly stressed and/or mass-produced products, for example in medical products and/or batteries for electromobility.

[0132] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.